An output level required of a super-conducting coil that uses a super-conducting wire is increasing year by year, and the electromagnetic force of such a coil is increasing correspondingly. Therefore, there are problems in that shearing stress generated in the super-conducting wire or between members forming the super-conducting coil is increased, which results in the separation of the material covering the super-conducting wire or of the members forming the super-conducting coil, and Joule heat generated upon occurrence of such separation induces a quench. In order to solve such problems, it is necessary to increase the bonding strength of the material covering the super-conducting wire and between the members forming the super-conducting coil so as to prevent the members from separation and thus suppress quenches.
In the conventional art, in order to increase the bonding strength between a winding portion of a super-conducting wire and an insulating plate, for example, ingenuity is exercised by inserting a resin material as a bonding material between the superconductor and the insulating plate, thereby improving the resistance to shearing stress.